1. Field of the Invention
The invention relates to a specifically embossed web or sheet exhibiting a high perceived softness. The invention further relates to a roll of embossed tissue. The embossed tissue of the invention results in superior overall appearance of the product as well as a consumer perception of improved softness. The embossed tissue of the present invention also results in a more uniform roll of tissue.
2. Background of the Invention
Tissue produced using conventional wet press technology must usually be embossed subsequent to creping to improve bulk, appearance and perceived softness. It is known in the art to emboss sheets comprising multiple plies of creped tissue to increase the surface area of the sheets thereby enhancing their bulk and moisture holding capacity. Toilet tissue is usually marketed in rolls, containing a specified number of sheets per roll. Tissue embossed in conventional patterns of spot debossments, when packaged in roll form, exhibit a tendency to be non-uniform in appearance often due to uneven buildup of the bosses as the sheet is wound onto the roll, resulting in a ridging effect detracting from the appearance of the rolls.
Prior art embossing patterns and methods of forming them have been set forth which emboss products in a manner selected to avoid nesting of the bosses in rolled, folded or stacked sheets of paper product by various means. For one example of such a pattern and method see U.S. Pat. No. 4,659,608. This prior art pattern while improving the nesting problem associated with previous prior art patterns, to only four locations, was faced with a spiralling effect similar to the visual spinning of a barber shop pole. In addition, this prior art pattern has stresses placed upon the boss pattern causing it to wrinkle and ridge.
A primary advantage of the present invention is to provide an embossed tissue which avoids buildup and ridging problems while heightening the consumer's perception of softness. The pattern which is formed in the tissue of the present invention may be formed by debossing or embossing. When an emboss pattern is formed, the reverse side of the sheet retains a deboss pattern. The projections which are formed are referred to as bosses. When a deboss pattern is formed, the reverse side of the sheet retains an emboss pattern and the projections are still referred to as bosses. Thus, the methodologies may be interchanged while producing the same product.
The product according to the present invention may include stitch-like bosses, signature bosses and/or finishing bosses. Signature bosses may be made up of any embossing design. They are most often a design which may be related by consumer perception to the particular manufacturer of the tissue.
Finishing bosses may also be made up of any embossing design. They too may be related by consumer perception to a specific manufacturer. The finishing bosses function in essentially the same manner regardless of the aesthetic design. Preferred aesthetic finishing bosses include cross-stitches, patchwork, hearts, flowers and the like.
According to the present invention, when the web or sheets are formed into a roll, the tissue is aligned so that the bosses are internal to the roll and the debossed side of the tissue is exposed.
In one embodiment of the present invention, the boss pattern combines relatively shallow stitchlike bosses with deeper more sharply defined signature bosses. The overall arrangement of the pattern is selected so that, even though each sheet or web is embossed heavily in the signature bosses, when the sheets are formed into a roll, the signature bosses fully overlap at a maximum of two locations in the roll, the outermost of these being at least a predetermined distance, e.g. about an eighth of an inch, inward from the exterior surface of the roll. Moreover, the overall average boss density is substantially uniform in the machine direction of each strip in the roll. The combined effect of this arrangement is that the rolls possess very good roll structure and do not exhibit the ridging effect found with prior art embossed tissue patterns.
In another embodiment of the present invention, a finishing boss is also included which is more shallow than the aforementioned stitchlike boss.
This invention further relates to the discovery that the perceived softness of embossed tissue can be increased greatly if a particular pattern is embossed into the tissue. This pattern combines bosses formed by relatively shallow stitchlike embossments or debossments with bosses formed by deeper more sharply defined embossments or debossments. When viewing the tissue from the debossed side, the shallow, stitchlike bosses are positioned to give a "puffy" quilted appearance to the areas defined by them, creating both actual shading and the illusion of shading as would be seen in a quilt having chambers filled with fiber or down. This appearance results from the use of stitchlike bosses which may be rounded and which are arranged in intersecting lines, preferably wavy flowing lines, both to simulate the appearance of stitches of a quilt as well as to distort the actual shape of the quilt so that the shape and appearance cooperate to reinforce the "quiltlike" appearance. The preferred waviness of the lines simulates the appearance of stitching displaced from straight lines by the filling in the quilt while creating the appearance of shading resulting from a three dimensional shape. In addition, the wavy flowing lines of these stitchlike bosses actually distort the sheet producing a shape resembling the surface of a filled quilt.
Signature and finishing bosses in regions framed by the intersecting flowing lines serve to greatly enhance the bulk of the tissue while also enhancing the distortion of the surface thereof. The signature bosses are continuous rather than stitchlike, can preferably be elongate, and are embossed or debossed to significantly greater depth and have more sharply defined boundaries than the bosses defining the wavy flowing lines. The finishing bosses are continuous or stitchlike and are embossed or debossed to less depth than the bosses defining the wavy lines. In addition, the signature bosses further enhance puffy or filled appearance of the sheet both by creating the illusion of shading as well as by creating actual shading due to displacement of the sheet apparently caused by puckering of surrounding regions due to the heavy embossing or debossing given to the signature.